Infographic: How Weight Lifting Changes Monkeys’ Neural Connections

After weeks of training, the muscles of two macaques exhibited greater responses to stimulation of the reticulospinal tract in the brain stem than they had before, suggesting that strengthening the neural pathway is key to getting stronger. 

Jef Akst
Jef Akst

Jef Akst is managing editor of The Scientist, where she started as an intern in 2009 after receiving a master’s degree from Indiana University in April 2009 studying the mating behavior of seahorses.

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Oct 1, 2020

Over the course of two months, researchers trained macaque monkeys to lift more and more weight, until they were able to do the equivalent of a one-armed pull-up. When the researchers stimulated a bundle of nerves in the spinal cord known as the reticulospinal tract (RST), they saw increases in the resulting neuronal electrical signals in the monkeys’ arm muscles as training progressed, while they did not see the same consistent upward trend in the muscles’ responses to stimulation of the corticospinal tract (CST). The results suggest that RST connectivity may play a critical role in muscle strengthening.

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